Assertion : Alkyl benzene is not prepared by Friedel-Crafts alkylation of benzene. Reason : Alkyl halides are less reactive than acyl halides.

Step-by-step solution

The monoalkyl derivative first formed readily undergoes further alkylation at a still greater speed to produce polysubstituted products, and alkyl halide employed may also undergo an isomeric change. Due to these difficulties alkyl benzene is not generally prepared by Friedel-Craft's alkylation of benzene.